/* ----------------------------------------------------------------------
* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
*
* $Date:        19. March 2015
* $Revision: 	V.1.4.5
*
* Project: 	    CMSIS DSP Library
* Title:		arm_conv_partial_opt_q15.c
*
* Description:	Partial convolution of Q15 sequences.
*
* Target Processor: Cortex-M4/Cortex-M3
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*   - Redistributions of source code must retain the above copyright
*     notice, this list of conditions and the following disclaimer.
*   - Redistributions in binary form must reproduce the above copyright
*     notice, this list of conditions and the following disclaimer in
*     the documentation and/or other materials provided with the
*     distribution.
*   - Neither the name of ARM LIMITED nor the names of its contributors
*     may be used to endorse or promote products derived from this
*     software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
* -------------------------------------------------------------------- */

#include "arm_math.h"

/**
 * @ingroup groupFilters
 */

/**
 * @addtogroup PartialConv
 * @{
 */

/**
 * @brief Partial convolution of Q15 sequences.
 * @param[in]       *pSrcA points to the first input sequence.
 * @param[in]       srcALen length of the first input sequence.
 * @param[in]       *pSrcB points to the second input sequence.
 * @param[in]       srcBLen length of the second input sequence.
 * @param[out]      *pDst points to the location where the output result is written.
 * @param[in]       firstIndex is the first output sample to start with.
 * @param[in]       numPoints is the number of output points to be computed.
 * @param[in]       *pScratch1 points to scratch buffer of size max(srcALen, srcBLen) + 2*min(srcALen, srcBLen) - 2.
 * @param[in]       *pScratch2 points to scratch buffer of size min(srcALen, srcBLen).
 * @return  Returns either ARM_MATH_SUCCESS if the function completed correctly or ARM_MATH_ARGUMENT_ERROR if the requested subset is not in the range [0 srcALen+srcBLen-2].
 *
 * \par Restrictions
 *  If the silicon does not support unaligned memory access enable the macro UNALIGNED_SUPPORT_DISABLE
 *	In this case input, output, state buffers should be aligned by 32-bit
 *
 * Refer to <code>arm_conv_partial_fast_q15()</code> for a faster but less precise version of this function for Cortex-M3 and Cortex-M4.
 *
 *
 */

#ifndef UNALIGNED_SUPPORT_DISABLE

arm_status arm_conv_partial_opt_q15(
    q15_t *pSrcA,
    uint32_t srcALen,
    q15_t *pSrcB,
    uint32_t srcBLen,
    q15_t *pDst,
    uint32_t firstIndex,
    uint32_t numPoints,
    q15_t *pScratch1,
    q15_t *pScratch2)
{

    q15_t *pOut = pDst;                            /* output pointer */
    q15_t *pScr1 = pScratch1;                      /* Temporary pointer for scratch1 */
    q15_t *pScr2 = pScratch2;                      /* Temporary pointer for scratch1 */
    q63_t acc0, acc1, acc2, acc3;                  /* Accumulator */
    q31_t x1, x2, x3;                              /* Temporary variables to hold state and coefficient values */
    q31_t y1, y2;                                  /* State variables */
    q15_t *pIn1;                                   /* inputA pointer */
    q15_t *pIn2;                                   /* inputB pointer */
    q15_t *px;                                     /* Intermediate inputA pointer  */
    q15_t *py;                                     /* Intermediate inputB pointer  */
    uint32_t j, k, blkCnt;                         /* loop counter */
    arm_status status;                             /* Status variable */
    uint32_t tapCnt;                               /* loop count */

    /* Check for range of output samples to be calculated */
    if((firstIndex + numPoints) > ((srcALen + (srcBLen - 1u))))
    {
        /* Set status as ARM_MATH_ARGUMENT_ERROR */
        status = ARM_MATH_ARGUMENT_ERROR;
    }
    else
    {

        /* The algorithm implementation is based on the lengths of the inputs. */
        /* srcB is always made to slide across srcA. */
        /* So srcBLen is always considered as shorter or equal to srcALen */
        if(srcALen >= srcBLen)
        {
            /* Initialization of inputA pointer */
            pIn1 = pSrcA;

            /* Initialization of inputB pointer */
            pIn2 = pSrcB;
        }
        else
        {
            /* Initialization of inputA pointer */
            pIn1 = pSrcB;

            /* Initialization of inputB pointer */
            pIn2 = pSrcA;

            /* srcBLen is always considered as shorter or equal to srcALen */
            j = srcBLen;
            srcBLen = srcALen;
            srcALen = j;
        }

        /* Temporary pointer for scratch2 */
        py = pScratch2;

        /* pointer to take end of scratch2 buffer */
        pScr2 = pScratch2 + srcBLen - 1;

        /* points to smaller length sequence */
        px = pIn2;

        /* Apply loop unrolling and do 4 Copies simultaneously. */
        k = srcBLen >> 2u;

        /* First part of the processing with loop unrolling copies 4 data points at a time.
         ** a second loop below copies for the remaining 1 to 3 samples. */
        while(k > 0u)
        {
            /* copy second buffer in reversal manner */
            *pScr2-- = *px++;
            *pScr2-- = *px++;
            *pScr2-- = *px++;
            *pScr2-- = *px++;

            /* Decrement the loop counter */
            k--;
        }

        /* If the count is not a multiple of 4, copy remaining samples here.
         ** No loop unrolling is used. */
        k = srcBLen % 0x4u;

        while(k > 0u)
        {
            /* copy second buffer in reversal manner for remaining samples */
            *pScr2-- = *px++;

            /* Decrement the loop counter */
            k--;
        }

        /* Initialze temporary scratch pointer */
        pScr1 = pScratch1;

        /* Fill (srcBLen - 1u) zeros in scratch buffer */
        arm_fill_q15(0, pScr1, (srcBLen - 1u));

        /* Update temporary scratch pointer */
        pScr1 += (srcBLen - 1u);

        /* Copy bigger length sequence(srcALen) samples in scratch1 buffer */

        /* Copy (srcALen) samples in scratch buffer */
        arm_copy_q15(pIn1, pScr1, srcALen);

        /* Update pointers */
        pScr1 += srcALen;

        /* Fill (srcBLen - 1u) zeros at end of scratch buffer */
        arm_fill_q15(0, pScr1, (srcBLen - 1u));

        /* Update pointer */
        pScr1 += (srcBLen - 1u);

        /* Initialization of pIn2 pointer */
        pIn2 = py;

        pScratch1 += firstIndex;

        pOut = pDst + firstIndex;

        /* Actual convolution process starts here */
        blkCnt = (numPoints) >> 2;

        while(blkCnt > 0)
        {
            /* Initialze temporary scratch pointer as scratch1 */
            pScr1 = pScratch1;

            /* Clear Accumlators */
            acc0 = 0;
            acc1 = 0;
            acc2 = 0;
            acc3 = 0;

            /* Read two samples from scratch1 buffer */
            x1 = *__SIMD32(pScr1)++;

            /* Read next two samples from scratch1 buffer */
            x2 = *__SIMD32(pScr1)++;

            tapCnt = (srcBLen) >> 2u;

            while(tapCnt > 0u)
            {

                /* Read four samples from smaller buffer */
                y1 = _SIMD32_OFFSET(pIn2);
                y2 = _SIMD32_OFFSET(pIn2 + 2u);

                /* multiply and accumlate */
                acc0 = __SMLALD(x1, y1, acc0);
                acc2 = __SMLALD(x2, y1, acc2);

                /* pack input data */
#ifndef ARM_MATH_BIG_ENDIAN
                x3 = __PKHBT(x2, x1, 0);
#else
                x3 = __PKHBT(x1, x2, 0);
#endif

                /* multiply and accumlate */
                acc1 = __SMLALDX(x3, y1, acc1);

                /* Read next two samples from scratch1 buffer */
                x1 = _SIMD32_OFFSET(pScr1);

                /* multiply and accumlate */
                acc0 = __SMLALD(x2, y2, acc0);
                acc2 = __SMLALD(x1, y2, acc2);

                /* pack input data */
#ifndef ARM_MATH_BIG_ENDIAN
                x3 = __PKHBT(x1, x2, 0);
#else
                x3 = __PKHBT(x2, x1, 0);
#endif

                acc3 = __SMLALDX(x3, y1, acc3);
                acc1 = __SMLALDX(x3, y2, acc1);

                x2 = _SIMD32_OFFSET(pScr1 + 2u);

#ifndef ARM_MATH_BIG_ENDIAN
                x3 = __PKHBT(x2, x1, 0);
#else
                x3 = __PKHBT(x1, x2, 0);
#endif

                acc3 = __SMLALDX(x3, y2, acc3);

                /* update scratch pointers */
                pIn2 += 4u;
                pScr1 += 4u;


                /* Decrement the loop counter */
                tapCnt--;
            }

            /* Update scratch pointer for remaining samples of smaller length sequence */
            pScr1 -= 4u;

            /* apply same above for remaining samples of smaller length sequence */
            tapCnt = (srcBLen) & 3u;

            while(tapCnt > 0u)
            {
                /* accumlate the results */
                acc0 += (*pScr1++ * *pIn2);
                acc1 += (*pScr1++ * *pIn2);
                acc2 += (*pScr1++ * *pIn2);
                acc3 += (*pScr1++ * *pIn2++);

                pScr1 -= 3u;

                /* Decrement the loop counter */
                tapCnt--;
            }

            blkCnt--;


            /* Store the results in the accumulators in the destination buffer. */

#ifndef  ARM_MATH_BIG_ENDIAN

            *__SIMD32(pOut)++ =
                __PKHBT(__SSAT((acc0 >> 15), 16), __SSAT((acc1 >> 15), 16), 16);
            *__SIMD32(pOut)++ =
                __PKHBT(__SSAT((acc2 >> 15), 16), __SSAT((acc3 >> 15), 16), 16);

#else

            *__SIMD32(pOut)++ =
                __PKHBT(__SSAT((acc1 >> 15), 16), __SSAT((acc0 >> 15), 16), 16);
            *__SIMD32(pOut)++ =
                __PKHBT(__SSAT((acc3 >> 15), 16), __SSAT((acc2 >> 15), 16), 16);

#endif /*      #ifndef  ARM_MATH_BIG_ENDIAN    */

            /* Initialization of inputB pointer */
            pIn2 = py;

            pScratch1 += 4u;

        }


        blkCnt = numPoints & 0x3;

        /* Calculate convolution for remaining samples of Bigger length sequence */
        while(blkCnt > 0)
        {
            /* Initialze temporary scratch pointer as scratch1 */
            pScr1 = pScratch1;

            /* Clear Accumlators */
            acc0 = 0;

            tapCnt = (srcBLen) >> 1u;

            while(tapCnt > 0u)
            {

                /* Read next two samples from scratch1 buffer */
                x1 = *__SIMD32(pScr1)++;

                /* Read two samples from smaller buffer */
                y1 = *__SIMD32(pIn2)++;

                acc0 = __SMLALD(x1, y1, acc0);

                /* Decrement the loop counter */
                tapCnt--;
            }

            tapCnt = (srcBLen) & 1u;

            /* apply same above for remaining samples of smaller length sequence */
            while(tapCnt > 0u)
            {

                /* accumlate the results */
                acc0 += (*pScr1++ * *pIn2++);

                /* Decrement the loop counter */
                tapCnt--;
            }

            blkCnt--;

            /* Store the result in the accumulator in the destination buffer. */
            *pOut++ = (q15_t) (__SSAT((acc0 >> 15), 16));

            /* Initialization of inputB pointer */
            pIn2 = py;

            pScratch1 += 1u;

        }

        /* set status as ARM_MATH_SUCCESS */
        status = ARM_MATH_SUCCESS;

    }

    /* Return to application */
    return (status);
}

#else

arm_status arm_conv_partial_opt_q15(
    q15_t *pSrcA,
    uint32_t srcALen,
    q15_t *pSrcB,
    uint32_t srcBLen,
    q15_t *pDst,
    uint32_t firstIndex,
    uint32_t numPoints,
    q15_t *pScratch1,
    q15_t *pScratch2)
{

    q15_t *pOut = pDst;                            /* output pointer */
    q15_t *pScr1 = pScratch1;                      /* Temporary pointer for scratch1 */
    q15_t *pScr2 = pScratch2;                      /* Temporary pointer for scratch1 */
    q63_t acc0, acc1, acc2, acc3;                  /* Accumulator */
    q15_t *pIn1;                                   /* inputA pointer */
    q15_t *pIn2;                                   /* inputB pointer */
    q15_t *px;                                     /* Intermediate inputA pointer  */
    q15_t *py;                                     /* Intermediate inputB pointer  */
    uint32_t j, k, blkCnt;                         /* loop counter */
    arm_status status;                             /* Status variable */
    uint32_t tapCnt;                               /* loop count */
    q15_t x10, x11, x20, x21;                      /* Temporary variables to hold srcA buffer */
    q15_t y10, y11;                                /* Temporary variables to hold srcB buffer */


    /* Check for range of output samples to be calculated */
    if((firstIndex + numPoints) > ((srcALen + (srcBLen - 1u))))
    {
        /* Set status as ARM_MATH_ARGUMENT_ERROR */
        status = ARM_MATH_ARGUMENT_ERROR;
    }
    else
    {

        /* The algorithm implementation is based on the lengths of the inputs. */
        /* srcB is always made to slide across srcA. */
        /* So srcBLen is always considered as shorter or equal to srcALen */
        if(srcALen >= srcBLen)
        {
            /* Initialization of inputA pointer */
            pIn1 = pSrcA;

            /* Initialization of inputB pointer */
            pIn2 = pSrcB;
        }
        else
        {
            /* Initialization of inputA pointer */
            pIn1 = pSrcB;

            /* Initialization of inputB pointer */
            pIn2 = pSrcA;

            /* srcBLen is always considered as shorter or equal to srcALen */
            j = srcBLen;
            srcBLen = srcALen;
            srcALen = j;
        }

        /* Temporary pointer for scratch2 */
        py = pScratch2;

        /* pointer to take end of scratch2 buffer */
        pScr2 = pScratch2 + srcBLen - 1;

        /* points to smaller length sequence */
        px = pIn2;

        /* Apply loop unrolling and do 4 Copies simultaneously. */
        k = srcBLen >> 2u;

        /* First part of the processing with loop unrolling copies 4 data points at a time.
         ** a second loop below copies for the remaining 1 to 3 samples. */
        while(k > 0u)
        {
            /* copy second buffer in reversal manner */
            *pScr2-- = *px++;
            *pScr2-- = *px++;
            *pScr2-- = *px++;
            *pScr2-- = *px++;

            /* Decrement the loop counter */
            k--;
        }

        /* If the count is not a multiple of 4, copy remaining samples here.
         ** No loop unrolling is used. */
        k = srcBLen % 0x4u;

        while(k > 0u)
        {
            /* copy second buffer in reversal manner for remaining samples */
            *pScr2-- = *px++;

            /* Decrement the loop counter */
            k--;
        }

        /* Initialze temporary scratch pointer */
        pScr1 = pScratch1;

        /* Fill (srcBLen - 1u) zeros in scratch buffer */
        arm_fill_q15(0, pScr1, (srcBLen - 1u));

        /* Update temporary scratch pointer */
        pScr1 += (srcBLen - 1u);

        /* Copy bigger length sequence(srcALen) samples in scratch1 buffer */


        /* Apply loop unrolling and do 4 Copies simultaneously. */
        k = srcALen >> 2u;

        /* First part of the processing with loop unrolling copies 4 data points at a time.
         ** a second loop below copies for the remaining 1 to 3 samples. */
        while(k > 0u)
        {
            /* copy second buffer in reversal manner */
            *pScr1++ = *pIn1++;
            *pScr1++ = *pIn1++;
            *pScr1++ = *pIn1++;
            *pScr1++ = *pIn1++;

            /* Decrement the loop counter */
            k--;
        }

        /* If the count is not a multiple of 4, copy remaining samples here.
         ** No loop unrolling is used. */
        k = srcALen % 0x4u;

        while(k > 0u)
        {
            /* copy second buffer in reversal manner for remaining samples */
            *pScr1++ = *pIn1++;

            /* Decrement the loop counter */
            k--;
        }


        /* Apply loop unrolling and do 4 Copies simultaneously. */
        k = (srcBLen - 1u) >> 2u;

        /* First part of the processing with loop unrolling copies 4 data points at a time.
         ** a second loop below copies for the remaining 1 to 3 samples. */
        while(k > 0u)
        {
            /* copy second buffer in reversal manner */
            *pScr1++ = 0;
            *pScr1++ = 0;
            *pScr1++ = 0;
            *pScr1++ = 0;

            /* Decrement the loop counter */
            k--;
        }

        /* If the count is not a multiple of 4, copy remaining samples here.
         ** No loop unrolling is used. */
        k = (srcBLen - 1u) % 0x4u;

        while(k > 0u)
        {
            /* copy second buffer in reversal manner for remaining samples */
            *pScr1++ = 0;

            /* Decrement the loop counter */
            k--;
        }


        /* Initialization of pIn2 pointer */
        pIn2 = py;

        pScratch1 += firstIndex;

        pOut = pDst + firstIndex;

        /* Actual convolution process starts here */
        blkCnt = (numPoints) >> 2;

        while(blkCnt > 0)
        {
            /* Initialze temporary scratch pointer as scratch1 */
            pScr1 = pScratch1;

            /* Clear Accumlators */
            acc0 = 0;
            acc1 = 0;
            acc2 = 0;
            acc3 = 0;

            /* Read two samples from scratch1 buffer */
            x10 = *pScr1++;
            x11 = *pScr1++;

            /* Read next two samples from scratch1 buffer */
            x20 = *pScr1++;
            x21 = *pScr1++;

            tapCnt = (srcBLen) >> 2u;

            while(tapCnt > 0u)
            {

                /* Read two samples from smaller buffer */
                y10 = *pIn2;
                y11 = *(pIn2 + 1u);

                /* multiply and accumlate */
                acc0 += (q63_t) x10 * y10;
                acc0 += (q63_t) x11 * y11;
                acc2 += (q63_t) x20 * y10;
                acc2 += (q63_t) x21 * y11;

                /* multiply and accumlate */
                acc1 += (q63_t) x11 * y10;
                acc1 += (q63_t) x20 * y11;

                /* Read next two samples from scratch1 buffer */
                x10 = *pScr1;
                x11 = *(pScr1 + 1u);

                /* multiply and accumlate */
                acc3 += (q63_t) x21 * y10;
                acc3 += (q63_t) x10 * y11;

                /* Read next two samples from scratch2 buffer */
                y10 = *(pIn2 + 2u);
                y11 = *(pIn2 + 3u);

                /* multiply and accumlate */
                acc0 += (q63_t) x20 * y10;
                acc0 += (q63_t) x21 * y11;
                acc2 += (q63_t) x10 * y10;
                acc2 += (q63_t) x11 * y11;
                acc1 += (q63_t) x21 * y10;
                acc1 += (q63_t) x10 * y11;

                /* Read next two samples from scratch1 buffer */
                x20 = *(pScr1 + 2);
                x21 = *(pScr1 + 3);

                /* multiply and accumlate */
                acc3 += (q63_t) x11 * y10;
                acc3 += (q63_t) x20 * y11;

                /* update scratch pointers */
                pIn2 += 4u;
                pScr1 += 4u;

                /* Decrement the loop counter */
                tapCnt--;
            }

            /* Update scratch pointer for remaining samples of smaller length sequence */
            pScr1 -= 4u;

            /* apply same above for remaining samples of smaller length sequence */
            tapCnt = (srcBLen) & 3u;

            while(tapCnt > 0u)
            {
                /* accumlate the results */
                acc0 += (*pScr1++ * *pIn2);
                acc1 += (*pScr1++ * *pIn2);
                acc2 += (*pScr1++ * *pIn2);
                acc3 += (*pScr1++ * *pIn2++);

                pScr1 -= 3u;

                /* Decrement the loop counter */
                tapCnt--;
            }

            blkCnt--;


            /* Store the results in the accumulators in the destination buffer. */
            *pOut++ = __SSAT((acc0 >> 15), 16);
            *pOut++ = __SSAT((acc1 >> 15), 16);
            *pOut++ = __SSAT((acc2 >> 15), 16);
            *pOut++ = __SSAT((acc3 >> 15), 16);


            /* Initialization of inputB pointer */
            pIn2 = py;

            pScratch1 += 4u;

        }


        blkCnt = numPoints & 0x3;

        /* Calculate convolution for remaining samples of Bigger length sequence */
        while(blkCnt > 0)
        {
            /* Initialze temporary scratch pointer as scratch1 */
            pScr1 = pScratch1;

            /* Clear Accumlators */
            acc0 = 0;

            tapCnt = (srcBLen) >> 1u;

            while(tapCnt > 0u)
            {

                /* Read next two samples from scratch1 buffer */
                x10 = *pScr1++;
                x11 = *pScr1++;

                /* Read two samples from smaller buffer */
                y10 = *pIn2++;
                y11 = *pIn2++;

                /* multiply and accumlate */
                acc0 += (q63_t) x10 * y10;
                acc0 += (q63_t) x11 * y11;

                /* Decrement the loop counter */
                tapCnt--;
            }

            tapCnt = (srcBLen) & 1u;

            /* apply same above for remaining samples of smaller length sequence */
            while(tapCnt > 0u)
            {

                /* accumlate the results */
                acc0 += (*pScr1++ * *pIn2++);

                /* Decrement the loop counter */
                tapCnt--;
            }

            blkCnt--;

            /* Store the result in the accumulator in the destination buffer. */
            *pOut++ = (q15_t) (__SSAT((acc0 >> 15), 16));


            /* Initialization of inputB pointer */
            pIn2 = py;

            pScratch1 += 1u;

        }

        /* set status as ARM_MATH_SUCCESS */
        status = ARM_MATH_SUCCESS;

    }

    /* Return to application */
    return (status);
}

#endif	/*	#ifndef UNALIGNED_SUPPORT_DISABLE	*/


/**
 * @} end of PartialConv group
 */
